Nowadays, the system of inoculation of biological samples onto the agar surface, suffers from a basic problem and a noteworthy rise in price is derived from it, aside from the fact that the microorganism colony count may be falsified.
This problem consists in that inoculation (whether or not it is spiral) onto the gel of the Petri capsule, requires a duct that is initially run through in the direction of suction so that the sample is lodged in a chamber from which the programmed dose will be poured by means of operating a small cylinder, the sample running the opposite path. The sample admitted for analysis, obviously contained microorganisms and therefore after inoculation, it has to be subjected to a thorough cleaning stage in order to prevent contamination of the next sample. Therefore, the tube that has become dirty with microorganisms, is washed with bleach and then rinsed several times to eliminate the microorganisms, given that if it has not been rinsed thoroughly, the bleach itself kills the microorganisms of the following analysis. This implies a very serious problem that falsifies the count to a larger or smaller degree.
Therefore, a continuous tube that becomes entirely dirty and that has in series a closing or nipping valve and that after being nipped the ram is moved so that the desired amount of liquid comes out, is used in the conventional inoculation system.